It is not always a problem because a parent should remain sensitive to situations where it is used. IYKYK in itself is not a problem but when kids are playing it to conceal something or to isolate someone or to evade a conversation on some subject, then it might be time to have a soft talk. In the majority of cases, however, it is just a fun slang word that children apply to show their belonging to a group of friends. Open communication may assist parents to know whether the usage is casual or it may be alarming. Know more about Iykyk meaning